The main engine manufacturers acknowledge that low load ops are leading to a required change in cylinder lube oil management. It is now no longer the simple act of balancing fuel sulphur with Base Number and feed rate. The load and relative temperature of the liner will require monitoring to ensure that conditions are avoided which can cause cold corrosion.
Honing marks removed due to corrosion
IN ALL CASES ROUTINE “CORRECTED” CDO ANALYSIS IS RECOMMENDED
In addition the modern lower BN products may not be ideal in all circumstances – I recommend a thorough review of the CLO management process when working a low load operational policy.
Files are attached for convenience
Wartsila CLO low load RT-148
Wartsila Lubes RT-138
MAN Diesel and Turbo SL2013-571
CLO feed rate optimising proc 2013-05-31
More and more CBM activities in shipping mean that the industry is finally starting to move!
Click to view SL2012-522 Main Bearing Inspection
Man Diesel now state clearly that bearing removal is not recommended as normal practice and therefore not recommended unless evidence based reason dictates.
This is a clear indication that best practice has shifted from a direct inspection methodology to a condition based approach.
This represents a shift in emphasis where the OEM clearly states that opening bearings without cause is likely to increase the risk of issue, either directly by the introduction of new sources of failure such as dirt or re-build issues, or by implication by reducing the support in terms of warrantee, where non recommended strip down may in the future invalidate terms.
Herein a video of the process for bearing removal courtesy of Marine Insight (Apologies for corrupted quality at the end! DS)
Classification and Condition Monitoring
One of the things that seems unusual is that whilst approximately 10% of classed vessels have their planned maintenance systems recognised by their classification society. This allows the Chief Engineer to credit a number of items for survey at some convenient time, only about 10% of these use approved condition monitoring process which the Chief can use to avoid opening these assets purely for the purposes of satisfying the regulatory requirement.
What that means is that only 1% of ships use condition monitoring for the purposes of classification. It is suspected that a significant number of vessels successfully employ some form of condition monitoring on a regular basis and may even use condition as a foundation for their maintenance strategy but do not take up the opportunity to align these processes with their classification society and therefore must be performing unnecessary invasive surveys and in doing so increasing the risk to reliability.
Why is this?
The world of the marine engineer is changing and instead of maintaining machines best practice is to maintain reliability. What I mean by this is that the act of maintenance has traditionally been one based upon the performance of tasks at predetermined intervals. These would vary in scale from simple checks and cleaning to performing a full strip down for overhaul and component renewal. Therefore the required skill was to be able to understand how to perform these tasks and return the machine successfully into service.As a result of improvements in design and a tendency to reduce the need for running repairs, there has been an increase in the use of throwaway components, e.g. sealed for life bearings. Coupled with the ever present need to operate at reduced cost means that more often nowadays the engineer is tasked with developing strategies to understand and react to condition thus avoiding or extending scheduled intervals of intervention until necessary. This approach is broadly described as a risk based approach. The engineer is now not maintaining the machine but maintaining the reliability of the machine.
The question to be answered is whether the emerging technologies and practices can be adequately implemented using staff who’s training is based upon traditional engineering principles when what is required is different. Not that engineers are not competent or sufficiently skilled to adapt, but whether the companies who employ them have developed and matured sufficiently to allow them to work in a different way.
Maintenance handbooks produced by manufacturers must by definition stipulate activities for every end user to reach an acceptable degree of reliability. This means that in the main most machines MUST be either over maintained or being maintained in a way that relieves the manufacturer of any liability in the event of a failure within the period of guarantee. Even when machines are in service beyond the traditional period for which guarantees are in place, in the event of a failure sufficiently significant to invoke the need for a claims or loss adjustment exercise, the company in question will find itself at higher risk of penalty due to reduced cover.
This the employed skills, the company culture and the risk protection devices are misaligned when compared to industry best practice. It is easier to employ traditional and hence sub-optimal methods to maintain machines in the marine industry.